1. Field of the Invention
The present invention relates to a wire harness including therein both electric wires for a low-voltage circuit and electric wires for a high-voltage circuit, and to a method for manufacturing the same.
2. Description of the Related Art
Recently has been developed an automobile in which loads in a 14 volts series and loads in a 42 volts series are mingled together. The automobile is mounted with a low-voltage power supply for 14V and a high-voltage power supply for 42V in the interior thereof. The high-voltage power supply is preferably connected to a motor generator, which is advantageous to fuel consumption. Therefore, it is necessary to provide two kinds of wire harnesses, namely a wire harness for electric wires used for the 42V series circuit and a wire harness for electric wires used for the 14V series circuit. However, it is difficult to lay two kinds of wire harnesses through different paths because the interior space of an automobile is limited.
In order to solve the above problem, a wire harness is disclosed in Japanese Patent Provisional Publication 2003-100155. As shown in FIG. 1, a wire harness 50 is formed by winding a constraint tape 51 around the external circumference of a bunch of electric wires including therein electric wires W1 for the 14V series circuit and electric wires W2 for the 42V series circuit.
Since the electric wires W1 and the electric wires W2 are contained together in the wire harness 50, a creepage distance D1 has a small value, wherein the creepage distance D1 corresponding to the shortest distance between the electric wires W1 and the electric wires W2. Therefore, as shown in FIG. 2, when openings 52 are formed on coating material of the electric wires W1 and the electric wires W2 due to collision of the vehicle, a leak current and/or an arc current will be generated within the wire harness 50. Further, as shown in FIG. 3, a leak current and/or an arc current will be generated at exposed portions 54 where the coating material is peeled off in order to connect branch electric wires 53 to the electric wires W1 and the electric wires W2. The electric wires W1 are also influenced by electromagnetic noise generated in the electric wires W2.